Process for preserving edible material



Patented June 15, 1937 PATENT OFFICE PROCESS FOR PREBEBVING EDIBLEMATERIAL Johan Olsen Nygaard, Oslo, Norway No Drawing. ApplicationOctober 12, 1934, Serial No. 748,137. In Norway September 24, 1931 6Claims. (cl. 99-158) This invention relates to a process of foodpreservation, and more particularly to the preservation for storage overa considerable period of time of the lean meat of whale, seal, and othersea mammals. It is the principal object of the invention to provide aprocess which permits the utilization of fleshy material of the largersea mammals heretofore discarded or only to a little degree utilized forlack of a suitable method of preserving and transporting the same.

For example, in the whaling industry the catch is ordinarily made in theice regions, in wholly uninhabited places frequently requiring a voyageof weeks or months to land. Enormous quantities of material suitable foredible or medicinal purposes such as the nonfatty portions of the flesh,the glands, 'the bones, and the internal organs of the whales, are oflittle or no value in the rendering of oil and are thrown overboard,this practice obviously involving a tremendous loss, particularly sincethe use of the whale for the extraction of the oil alone necessitates acatch of a much greater number of whales for profitable operation-thanwouldbe necessaryif substantially the whole of the whale could beconverted into a useful product. Obviously a possible result of thispractice is the extermination of the whale, it having been longappreciated that the experience of the whaling industry in northernwaters, where the whales have been killed off or driven away so thatwhaling is no longer profitable, is likely to be repeated in theAntarctic to which the whaling industry is now largely confined.-

It is of course most convenient and profitable to effect the renderingof the blubber at sea, but in spite of intensive work and many expensiveexperiments no usable and sufllciently productive practical method forthe whaling industry has heretofore been discovered for conserving theenormous quantities of leaner parts of the whale on board ship fortransport to the markets, and the storage of considerable quantities offlesh, bones and internal organs without preservation for the period oftime required to reach the market, frequently through the tropics to thenorthern hemisphere, is obviously impractical.

.By means of the present invention it'is possible in a practical way andeconomically to preserve and store such portions of the whale as haveheretofore been discarded without material depreciation fromdecomposition, pending the delivery of the material to distant placeswhere facilities for the completion of the treatment of the material foruse as food, or for medicinal or other purposes are available. It isthus possible to transfer this material from the Antarctic, in whichmore than of the whaling takes place at the present, to land stationsand markets for the product which are principally situated in theNorthern Hemisphere, the material being sumciently sterilized andpreserved to prevent decomposition on the trip through the tropicalzones.

More specifically it is an object of the invention to dehydrate thecomparatively fat-poor flesh, bones, and .internal organs of whales andother sea mammals by heating the same with oil, preferably derived fromthe mammals, the process preferably being carried out under reducedpressure in order to avoid high temperatures and consequent injury tothe tissues and the coagulation of albuminous matter.

In carrying out the process, the material undergoing treatment ispreferably comminuted by grinding, cutting, or pressing, for instance bythe employment of a mill which passes the material through a screenhaving apertures of from 12 to 20 mm. in diameter. The divided materialis then-introduced, together with a suflicient quantity of oil, into aclosed boiler having pressure control means associated therewith, thematerial and the oil being preferably whipped or stirred together eitherbefore or after introduction into the boiler to form a medium ofsemiliquid consistency. While the proportions of the comminuted materialand the oil may vary to a considerable extent, the boiler charge willnormally consist of three or four parts of oil to five parts ofmaterial.

The boiler may be heated by a steam jacket or by internal tubing throughwhich the steam is passed the initial heating being effected by steamwhich is maintained at a relatively low tempera.- ture, for instance byreduction of the steam pressure to 0.75 atmosphere to avoid violentboiling and the resultant carrying off of an excessive quantity of oiland solid particles. The temperature of the steam may be increasedduring the process until it reaches approximately 'C., corresponding toa pressure of about 2 atmospheres, or at least such a temperature thatthe material undergoing treatment is heated to about 60 C. It issometimes necessary to again reduce the steam temperature below 1atmosphere toward the end of the process owing to the gradual rise intemperature of the mixture. The temperature and pressure of the steammay be controlled in any convenient manner, for instance by throttlingthe steam.

Throughout the process the pressure on the material being treated withinthe boiler should be maintained as low as possible, a pressure of 0.2atmosphere giving excellent results in the treatment of flesh. Thetemperature of the material may thus be maintained relatively low, ithaving been found that a temperature of more than 90 C. isunsatisfactory, principally because of the coagulation of the albuminousmatter and the resultant encysting of a considerable portion of thematerial. As an example, if the material consists largely of liver,- thevacuum should be preferably reduced to an extent sufficient to ensureevaporation of the water in the material at 35 to 40 C. and thetemperature of the oil should at no stage of the process exceed 50 C.

Preferably the evaporated water discharged from the boiler is condensed,any entrained oil is separated out. and the water may be purified forsubsequent use in boilers for the rendering of oil from portions of theanimal which are richer in fat. The separated oil may then be employed,preferably while still hot, in the treatment of a fresh batch of rawmaterial, it being ordinarily necessary to introduce additional oil toreplace that absorbed by the relatively lean material.

When the dehydration of the material has proceeded to such an extentthat the water content of the material has been reduced to less than 10%and preferably about 6% or less, the material is withdrawn from theboiler and allowed to settle, the oil being withdrawn from the top, andthe material being preferably pressed to remove the major quantity ofthe remaining oil. By this method the oil content of the material may bebrought down to a practical minimum, experience indicating that aquantity of oil in an amount of about 10% to 12% of the material may beobtained and satisfactorily retained. With such an oil content thematerial may be easily transported pneumatically and may be delivered totanks for storage.

It is highly desirable not only to comminute the material, but to stirthe material during treatment thereof so that the water content may beevaporated rapidly and so that the various portions of the material willbe uniformly dried, portions such as sinews and the like which are morehydrous can be dried to an extent sufficient to avoid the subsequentformation of centers of putrefaction in the mass. Furthermore, by meansof constant agitation during the treatment the material as a whole maybe maintained at the desired temperature to prevent the destruction ofvaluable products and the final water content of the mass can be moreconveniently and accurately controlled. Conventional agitating meanswithin the boiler may be employed for this purpose.

It is found that this method of preservation is principally effectivefor two reasons. Thus not only is the raw material sterilized by drying,but the oil which surrounds the individual particles of the driedmaterial is sufficient to protect the material against moisture in theair, even though the greater portion of the oil has been removed fromthe material by pressing. The final product is in this mannersufficiently dried and preserved for transportation to distant placeswhere it may be subjected to further manufacturing processes renderingit wholly suitable for the intended purpose. The process further resultsin a substantial decrease in volume of the material, the raw comminutedflesh beingfor instance reduced to about one-quarter of'its originalvolume and weight, whereby storage problems are simplified.

It is a significant fact that the oil in which the lean material isprocessed need not be of edible grade. Thus, it is found that aninferior unrefined whale oil, such as is readily available on boardship, can be used. Even though an ill smelling and tasting train oil isused, no difliculty is encountered in the subsequent preparation of thematerial for food stuff. It is also found to be quite possible to useflesh which is partially fermented or decomposed and has acquired apulpy consistency by the destruction of the cellular tissue, whereasheretofore material in such condition has been thrown overboard whetherfatty or lean.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

1. A process for the preservation and storage on whaling vessels and thelike of bones and comparatively fat-poor parts, such as flesh andinternal organs of sea mammals which comprises dehydrating the rawmaterial by heating with train oil under reduced pressure and to atemperature not exceeding 90 0., and subsequently separating excess oilfrom the material.

2. A process for the preservation of flesh poor in fat, bones, andinternal organs of whales, seals and other sea mammals, which comprisescomminuting the material to be treated, mixing the material with acomparable quantity of train oil, heating the mixture to a temperaturesuflicient to drive off moisture under a pressure substantially lessthan atmospheric, removing the major portion of the oil by draining andpressing, and storing the dried material.

3. The method of treatment of the carcasses of marine mammals such aswhales, seals, or the like, which comprises separating from suchcarcasses the principal fat or oil containing portions, including theblubber, etc.; comminuting the remaining comparatively fat-poor portionsincluding the lean flesh, the internal organs, and the bones; mixing thecomminuted material with a sufficient quantity of oil to form asemi-solid mass; heating the mixture under reduced pressure and at atemperature not exceeding 90 G. until the major portion of the watercontent of the material is evaporated: and then removing the greaterportion of the oil.

4. The method of treatment of the carcasses of marine mammals such aswhales, seals, or the like, which is particularly adapted for use onshipboard, and which comprises separating from such carcasses theprincipal fat or oil containing portions including the blubber, etc.;comminuting the remaining comparatively fat-poor portions including thelean flesh, the internal organs, and the bones; mixing the comminutedmaterial with a suflicient quantity of oil obtained from said fattyportions of the carcasses to form a semi-solid mass; heating the mixtureat a pressure of the order of about 0.2 atmosphere and at a temperaturenot exceeding 90 C. for a sufficient length of time to evaporate thegreater portion of the moisture in the material; and then removing themajor portion of the oil.

5. The method of treatment of the carcasses of marine mammals such aswhales, seals, or the like, which is particularly adapted for use onshipboard and which comprises separating from such carcasses theprincipal fat or oil containing portions including the blubber, etc.;comminuting the remaining comparatively fat-poor portions including thelean flesh, the internal organs, and the bones; mixing the comminutedmaterial with a suflicient quantity of oil obtained from said fattyportions of the carcasses to form a semi-solid mass; heating the mixtureto a temperature ranging from about 35 C. to 60 C. and

at a pressure sumciently reduced to effect the evaporation of water fromthe material at such temperatures, and continuing the heating for alength of time sufficient to reduce the moisture content of the materialto less than 10%; and then removing the major portion of the oil bydraining and pressing.

6. The method of treatment of the carcasses of marine mammals such aswhales, seals, or the like, which is particularly adapted for use onshipboard, and which comprises separating from the carcasses theprincipal fat or oil containing portions including the blubber, etc.;comminuting the remaining comparatively fat-poor portions including thelean flesh, the internal organs, and the bones; mixing the comminutedmaterial with a sufficient quantity of oil obtained from said fattyportions of such carcasses to form a semisolid mass; heating the mixtureat a temperature not exceeding 90 C. for a length of time suflicient toevaporate the greater portion of the moisture in the material; and thenremoving the major portion of the oil.

JOHAN OLSEN NYGAARD.

